JP3757198B2 - Polypropylene resin composition - Google Patents

Description

【００４４】
【発明の効果】
本発明のポリプロピレン系樹脂組成物は、ポリプロピレン樹脂、エチレンと炭素数３以上のアルファオレフィンからなる部分を含む共重合体及び平均粒子径が３μｍ以下のタルクを混練し、極めて均一に分散した樹脂組成物である。
その結果、このポリプロピレン系樹脂組成物は、従来の同一系統の樹脂組成物に比較してタッピング強度、表面硬度（耐傷つき性）、常温及び低温（−３０℃）における耐衝撃性、流れ特性（フローマーク）等において優れており、物性値としてバランスのとれた特徴を有しているので射出成形、シート成形用材料として優れた原材料として使用できる。[0001]
[Industrial application fields]
The present invention is a high fluidity polypropylene resin composition that has high gloss, excellent scratch resistance, low shrinkage rate, little deformation such as warpage for a long time after molding, excellent tapping strength, and does not require much heat resistance. The present invention relates to a physical resin composition, particularly a resin composition useful as an exterior material for home appliances, office equipment and the like.
[0002]
[Prior art]
Isotactic crystalline polypropylene (hereinafter, polypropylene is referred to as PP) is relatively inexpensive, light in specific gravity, excellent in workability, and has an appropriate mechanical strength. As a composite material combined, it is widely used as a material for household goods, stationery, miscellaneous goods, containers for foodstuffs, packaging materials, home appliances, office equipment, and also transportation equipment such as automobiles.
However, in block-shaped molded products, PP tends to be deformed due to shrinkage, warpage, sink marks, etc. due to crystallinity with the passage of time after molding, and gloss may be lowered depending on the filler material. Although it itself is not related to luster, it may cause small scratches on the product surface, causing irregular reflection and loss of luster, and other industries such as home appliances and office equipment that require strong dimensional stability and design. In the product field, its share is low, and considering the price, mechanical properties, etc., its share is not high as a whole from a performance standpoint.
[0003]
In general, many proposals have been made to use fillers such as talc and glass fiber to suppress deformation due to warpage, sink marks, etc. caused by molding shrinkage. In addition, reduction in gloss due to filler material and shape is inevitable, and in the fields of home appliances, office equipment, home furniture, etc. that place emphasis on appearance and design, as a result, the type and amount of filler However, the raw material of such a molded product has a problem. In addition, fillers are used as fillers for resin modification and price reduction.
By the way, in the field of injection molding, there is a demand in the direction of mold enlargement, refinement, and low-temperature molding, and further improvement of fluidity without increasing the physical performance of the resin (improving MFR). Along with this, the development of a resin composition having a high MFR has been desired from the viewpoint of reducing the shrinkage of the molded product and improving the gloss. Increasing the PP MFR improves the crystallinity of the resin and improves the rigidity of the PP-based material blended with the rubber component. On the other hand, the molecular weight is reduced, which reduces other performance such as stress cracking. Inviting was inevitable.
[0004]
Even when fillers are used for the purpose of suppressing molding shrinkage or improving rigidity, if the MFR of PP is high, the melt viscosity of the entire resin is lowered, resulting in insufficient kneading, resulting in poor filler dispersion. As a result, the expected physical properties cannot be improved, and important gloss and scratch resistance are lowered.
As described above, in the PP resin composition for injection molding, there is a resin composition having excellent gloss, low shrinkage ratio (warp and sink) and scratch resistance, which are contradictory requirements while maintaining the physical properties of the PP resin itself. It was requested.
[0005]
[Problems to be solved by the invention]
The present invention has a high MFR, high gloss, excellent scratch resistance, stable shape retention after molding based on low shrinkage and no warp or sink, and excellent high tapping properties required for home appliances. The purpose is to develop a highly fluid polypropylene resin composition.
[0006]
[Means for Solving the Problems]
The present invention
[1] (A) MFR (JIS K-7210, melt flow rate measured according to Table 1, Condition 14) is 100 to 1000 g / 10 min, and propylene-linked isotactic pentad fraction (P) is Polypropylene resin of 0.980 or more (as a result of kneading all the polypropylene resins contained in the resin composition) ... 40 to 85 wt%,
(B) a component composed of one or more copolymers including a portion composed of ethylene exceeding 10 wt% and an alpha olefin having 3 or more carbon atoms (provided that propylene is at most 80 wt%) (provided that ethylene and 3 carbon atoms herein) The above-mentioned alpha olefin is not limited to the raw material monomer but means that the copolymer has as a structural unit.)... 50 to 10 wt%
(C) Talc with an average particle diameter of 3 μm or less 3 to 20 wt%
A composition comprising:
(1) The MFR of the entire composition is 25 g / 10 min or more, and
(2) Dispersion parameter (σ) of talc of (C) in the resin component consisting of (A) and (B) (horizontal axis is talc area fraction, vertical axis is frequency, approximated by Gaussian distribution) A standard deviation of the hour)), and a polypropylene-based resin composition characterized by being 4.5 or less,
[0007]
[2] The polypropylene resin composition according to the above [1], wherein the copolymer of the component (B) is a copolymer containing a portion composed of ethylene and an alpha olefin having 4 or more carbon atoms,
[3] An ethylene-propylene-alphaolefin terpolymer in which the copolymer of component (B) is composed of 10 to 80 wt% ethylene, 80 to 10 wt% propylene, and 10 to 80 wt% alpha olefin having 4 or more carbon atoms. The polypropylene resin composition according to the above [1] or [2],
[4] The above [1] or [2], wherein the copolymer of the component (B) is a hydrogenated product of a styrene-butadiene block copolymer or a random copolymer having a constitutional unit derived from styrene of 40 wt% or less. A polypropylene resin composition according to claim 1,
[5] The polypropylene series according to any one of [1] to [4], wherein the number average particle diameter of the copolymer particles of component (B) dispersed in the polypropylene resin of component (A) is 3 μm or less. Resin composition,
[0008]
[6] Isotactic which constitutes a part of polypropylene resin (A) having an MFR of 100 to 1000 g / 10 min and an isotactic pentad fraction (P) of 0.980 or more. After melt kneading with a polypropylene resin having a tick pentad fraction (P) of 0.960 or more and an MFR of 50 g / 10 min or less in advance, the remainder of the polypropylene resin (A) and the copolymer (B) are melt kneaded. [1] above, characterized in thatOr any of [5]The above object was achieved by developing the method for producing a polypropylene resin composition described in 1. above.
[0009]
PP used in the present invention is a random copolymer of alpha olefins such as isotactic PP (referred to as homo PP) or propylene as a main component, and a small amount (usually 10 wt% or less) of ethylene, butene-1. However, homo PP is most preferable from the viewpoint of physical properties such as rigidity and heat resistance. This PP means the property of the result of melt kneading all the polypropylene compositions contained in the polypropylene resin composition composition, and may be a mixture of polypropylene compositions having different MFR and the like. That is.
[0010]
In particular, from the standpoint of scratch resistance and tapping strength, the propylene chain isotactic pentad fraction (P) of PP is 0.980 or more, MFR is 100 to 1000 g / 10 min, preferably 150 to 800 g / 10 min. More preferably, 170 to 800 g / 10 min, particularly 200 to 800 g / 10 min is preferable, and it has been found that this can be achieved by using such PP. When the isotactic pentad fraction of the raw material PP is 0.980 or less, the scratch resistance and tapping strength of the polypropylene resin composition are lowered. The isotactic pentad fraction of the raw material PP is preferably 0.985 or higher, more preferably 0.990 or higher. In addition, when the MFR is 100 g / 10 min or less, the flowability of the obtained polypropylene resin composition is low. On the other hand, when the MFR is 1000 g / 10 min or more, the fluidity can be maintained high, but the impact strength and stress cracking strength are low because the molecular weight is small. It is not preferable because the physical properties such as
[0011]
The copolymer used for the component (B) of the present invention contains a structural unit derived from ethylene and an alpha olefin having 3 or more carbon atoms including propylene and butene-1. (However, the structural unit derived from the alpha olefin having 3 or more carbon atoms and ethylene mentioned here is not limited to the raw material monomer, and may be contained as a structural unit of the copolymer.)
[0012]
Furthermore, it has been found that a copolymer having a chain composed of structural units of ethylene and an alpha olefin having 4 or more carbon atoms can be used as the copolymer of the component (B). The portion consisting of structural units of ethylene and an alpha olefin having 4 or more carbon atoms is present at the interface with PP as a result of being compatible with PP, and achieves fine dispersion of the copolymer and physical properties of the polypropylene resin composition. It seems that it will greatly improve.
Specific examples of such a copolymer include an ethylene-butene-1 copolymer, an ethylene-hexene-1 copolymer, an ethylene-octene-1 copolymer, and an ethylene-propylene-alpha-olefin having 4 or more carbon atoms. Random copolymers such as terpolymers (eg, ethylene-propylene-butene-1 copolymer, ethylene-propylene-hexene-1 copolymer), hydrogenated-styrene-butadiene-random copolymers, ethylene Block copolymer having block and ethylene-butene block (hydrogenated-butadiene-block copolymer), block copolymer having block of styrene block and ethylene-butene (hydrogenated-styrene-butadiene-block copolymer) ) And the like.
[0013]
The copolymer of these components (B) is not particularly concerned for improving the gloss and shrinkage of the polypropylene resin composition, but affects the retention of physical properties such as strength and impact resistance. For this purpose, it is generally preferred to use a block copolymer, more preferably a hydrogenated-styrene-butadiene block copolymer. An ethylene-propylene-α-olefin terpolymer having 4 or more carbon atoms and a hydrogenated-styrene-butadiene random copolymer are also preferable copolymers. As the ethylene-propylene-alpha-olefin terpolymer having 4 or more carbon atoms, a copolymer having 10 to 80 wt% ethylene, 80 to 10 wt% propylene, and 10 to 80 wt% alpha-olefin having 4 or more carbon atoms. use. A copolymer of 15 to 50 wt% ethylene, 70 to 15 wt% propylene, and 15 to 50 wt% α-olefin having 4 or more carbon atoms is preferable.
[0014]
When a copolymer containing a structural unit derived from styrene is used as the copolymer of component (B), styrene needs to be 40 wt% or less in order to obtain the desired performance. When it is 40 wt% or more, the impact resistance is lowered.
[0015]
The compounding quantity of the copolymer of a component (B) is 50-10 wt%. When this is less than 10 wt%, the impact resistance of the polypropylene resin composition decreases. When the amount exceeds 50 wt%, the gloss and scratch resistance are remarkably impaired and the rigidity such as tapping strength is lowered, which is not preferable. A preferable blending amount is 20 to 40 wt%. A copolymer having an MFR of 2 g / 10 min or more is used. When using an MFR of less than 2 g / 10 min, not only will the flow characteristics of the polypropylene resin composition be lowered, but it will also be difficult to achieve fine dispersion of the copolymer, making it particularly effective in mechanical blending. This becomes a bottleneck in manufacturing the composition. When the number average particle diameter of the copolymer dispersed particles in the component (A) is 3 μm or less, the impact resistance and gloss are high, and the dispersion is poor and the average particle diameter is large. Is done.
[0016]
By further blending talc having an average particle diameter of 3 μm or less, preferably 1 μm or less, as the component (D) into the polypropylene resin composition of the present invention, the rigidity can be enhanced. This blending amount is glossy by using 3 to 20 wt% of talc of component (D) for 40 to 80 wt% of component (A), 50 to 10 wt% of component (B) and 3 to 20 wt% of component (C). Further, it is possible to reinforce the rigidity such as scratch resistance and tapping strength without impairing the shrinkage rate and impact resistance. Also in this case, the dispersion parameter (σ) of talc is 4.5 or less, preferably 4.0 or less, more preferably 3.5 or less.
[0017]
When the average particle size of talc exceeds 3 μm, not only the impact resistance is lowered but also the gloss is inevitably lowered. The blending ratio is 20 wt%, preferably 10 wt% or less. Even if talc having an average particle size of 3 μm or less is blended in excess of 20 wt%, poor dispersion occurs, and a significant reduction in impact resistance and gloss is inevitable. If the blending amount is less than 3 wt%, there is almost no effect on the rigidity of the polypropylene resin composition.
The polypropylene resin composition of the present invention needs to maintain high fluidity in addition to the desired high gloss, low shrinkage, high scratch resistance, and high tapping strength, so the overall MFR is 35 g / 10. More than a minute is required. Preferably it is 40 g / 10 min or more, more preferably 45 g / 10 min or more.
[0018]
Although it does not specifically limit as a means for manufacturing the polypropylene resin composition of this invention, The method of carrying out a normal blend is employable. In this case, a single-screw or twin-screw extruder may be used, but it is preferable to use a twin-screw extruder having a kneading effect if possible.
Rather than kneading the powder directly into the resin, talc is produced by once producing a masterbatch using a resin in which these fillers are easy to disperse, and blending this masterbatch with other components constituting the resin composition. A polypropylene resin composition with good filler dispersion can be produced.
[0019]
Specifically, the polypropylene resin composition of the component (A) having an isotactic pentad fraction (P) of 0.960 or more and a relatively high MFR of 50 g / 10 min or less is previously used as the filler component. By melt-kneading with polypropylene constituting a part, uniform dispersion of the filler is promoted, and a polypropylene resin composition having a dispersion parameter (σ) of 4.5 or less is obtained. Scratch resistance and tapping strength are improved while maintaining impact and gloss. In order to further improve these physical properties, it is preferable that the isotactic pentad fraction (P) of the polypropylene to be melt-kneaded is 0.70 or more. More preferably, it is 0.980 or more, Most preferably, it is 0.990 or more.
[0020]
As described above, when a polypropylene resin having a relatively low MFR and an inorganic filler are melt-kneaded in advance as described above, the dispersion of the inorganic filler in the composition is promoted to be uniform and the physical properties are improved, but the mechanism has not been clarified. I believe that.
In order to maximize the performance of an inorganic filler such as calcium carbonate, it is necessary to uniformly disperse it in the polypropylene resin (A) constituting the composition. Generally, an inorganic filler such as calcium carbonate is used. In order to disperse, a shearing force larger than that of the elastomer component such as component (B) is required. Therefore, when all the resin components containing high MFRPP and the inorganic filler are kneaded at the same time, it is estimated that the component (A) used in the present invention has a low melt viscosity, so that sufficient shear stress to disperse the inorganic filler cannot be obtained. Is done. Therefore, it is considered that a preferable result can be obtained by previously dispersing the inorganic filler in PP having a high melt viscosity and then kneading the component (B) and the remaining high MFRPP.
[0021]
In the polypropylene resin composition of the present invention, all additives such as a thermal oxidation stabilizer, a nucleating agent, a light stabilizer, a lubricant and the like, which are blended in a normal polypropylene resin composition, can be used as necessary. Further, it may be partially modified using a radical initiator such as peroxide or a modifier such as unsaturated carboxylic acid. In particular, in order to improve rigidity, the combined use of a nucleating agent is a preferred embodiment.
The polypropylene resin composition of the present invention can be used alone, or can be used by blending other various thermoplastic resins such as olefin polymers such as polyethylene and polybutene.
[0022]
[Action]
There are several proposals such as proposals to use fillers to improve the physical properties of PP, such as rigidity, heat resistance, or blend rubber-based materials to improve low temperature impact resistance, It is well known that they can be effective as such. Among them, there are many examples in which a block copolymer is blended as a rubber component with PP as in the resin component of the present invention, but there are hardly any systems in which the MFR of PP is extremely high as in the present invention. It is assumed that the use of such a high MFR can be easily estimated that the strength and impact resistance are greatly reduced.
To solve this problem, the rubber component and talc containing an ethylene-α-olefin structural unit are uniformly added to PP having an extremely high MFR but an isotactic pentad fraction (P) of 0.980 or more. It was solved by developing a polypropylene resin composition obtained by dispersing. It was revealed that this product is high flow and has a heat resistant polypropylene resin composition excellent in impact resistance, rigidity and low shrinkage.
[0023]
【Example】
(Example)
Examples of the present invention will be described below, but the present invention is not limited thereto. [Measurement method]
Various physical properties were measured by the following methods.
(1) Measurement of isotactic pentad fraction (P)
¹³Using data obtained by C-NMR, A. Zambelli et al. (Macromolecules,6925 (1973)).
(2) Composition of ethylene-propylene-alpha olefin copolymer
¹³It calculated using the data calculated | required by C-NMR.
(3) MFR
Measured according to JIS K-7210 Table 1, Condition 14 (test temperature 230 ° C., test load 2.16 kgf).
[0024]
(4) Izod impact strength
The test was performed using a notched test piece according to ASTM D256.
(5) Flexural modulus
Measured according to ASTM D790.
(6) Gloss
A test piece of length 120 mm x width 120 mm x thickness 2 mm from a flat plate manufactured using a Toshiba injection molding machine (1S170F2) (temperature: 230 ° C, injection speed: 25 mm / min, injection time: 30 seconds). It cut out and measured with the light source incident angle and light reception angle of 60 degree | times with Nippon Denshoku Industries Co., Ltd. VG-1D type | mold gloss meter.
(7) Appearance (flow mark observation)
Visual measurement was performed using a flat plate similar to that used for the gloss evaluation. In the evaluation, Δ: a flow mark is observed. ◯: There are almost no flow marks. A: There is no flow mark at all.
[0025]
(8) Shrinkage rate (change in dimension of molded product)
For a flat plate similar to that used for the gloss evaluation, the dimension (α mm) in the resin flow direction (referred to as MD direction) and the dimension (β mm) in the direction perpendicular to the resin flow direction (referred to as TD direction) were measured. After molding, it was measured after standing for 48 hours in a thermostatic chamber at a temperature of 23 ° C. and a humidity of 50%.
MD direction shrinkage (%) = 100 (α−γ) / γ
Shrinkage rate in TD direction (%) = 100 (β−γ) / γ
However, (gamma) represents metal mold | die original dimension (mm).
[0026]
(9) Average particle size of copolymer (B), calcium carbonateAndTalc(C)Of dispersion parameter (σ) of
  The average particle diameter of the copolymer, the dispersion parameter (σ) of calcium carbonate and talc were all measured by image analysis of a transmission electron microscope (hereinafter referred to as TEM) photograph. A sample for a TEM photograph was 1 cm long from a test piece having a thickness of 3 mm produced using an injection molding machine (1S170F2) manufactured by Toshiba Corporation (temperature: 230 ° C., injection speed: 25 mm / min, injection time: 30 seconds). × Cut out a block of 5 mm in width × 3 mm in height, and made an ultrathin piece with a thickness of 60 nm with an ultramicrotome (ULTRACUT UN, diamond knife manufactured by Reichert) and collected it on a copper mesh. The copolymer was dyed by standing in steam. TEM observation is
Apparatus: An H-800 transmission electron microscope (resolution: 2.0 angstrom (lattice image)) manufactured by Hitachi, Ltd. was used.
  In the obtained TEM photographic image, the inorganic filler is generally black, the copolymer is gray, and the matrix PP is white.
  Next, based on the photograph obtained by the above TEM observation, Toshiba Corporation image processor TOSPIX-U2 (screen size: vertical 1024 x horizontal 1024 x depth 8 (pixels / sheet)), grayscale: 256 floors Image analysis was performed using the high-accuracy monitor particle analysis package of the tone image processor.
  As a document relating to these image analysis, there is “Image processing applied technology” by Hiroshi Tanaka: published by Industrial Research Council, July 1, 1989.
[0027]
(9) -1 Measurement of average particle diameter of copolymer (B)
The average particle size of the copolymer is the number average particle size of the copolymer after reading the grayscale image obtained from the TEM photograph using the above image processing apparatus and converting it to a binary image of white or black. Asked.
(9) -2 Measurement of dispersion parameter (σ) of talc or talc and calcium carbonate
In the present invention, the dispersion parameter (σ) of talc or talc and calcium carbonate is an index of the uniformity of dispersion of talc or talc and calcium carbonate in the resin composition. Specifically, it is the standard deviation of the area fraction of talc or talc and calcium carbonate, and is measured as follows.
A 36 μm × 48 μm TEM photograph was divided into 48 visual fields, and the area fraction for each visual field was determined. The area fraction was calculated by converting the read gray image into a binarized image consisting of talc and resin, and then dividing the area of the talc and calcium carbonate parts by the area of the read visual field.
The area fraction of talc or talc and calcium carbonate thus obtained was plotted on the horizontal axis, the frequency of the area fraction was plotted on the vertical axis, and the obtained statistical distribution was calculated as a numerical value approximated by the following Gaussian function. . The standard deviation (σ) of the function obtained at this time was used as a dispersion parameter.
Y = Y_m ・ Exp [-(XX_m )² / 2σ² ]
Y: Height when the area fraction X of talc is X.
Y_m : Peak area fraction X_m The height at the time.
σ: Standard deviation of area fraction.
[0028]
(10) Sled
A test piece (disk: diameter: 12.5 mm, thickness: 2.3 mm) was manufactured by injection molding at a resin temperature of 210 ° C. with a pinpoint gate from the center. Each disc obtained was left in a constant temperature room at 23 ° C. for 40 hours, and then the average of five pieces of warp (mm) was obtained.
(11) Scratch resistance
Using a surface property measuring instrument (HEIDON 14S / D), with a conical scratching needle (Sapphire: JIS K-6719 standard product) on the surface of the test piece (vertical 150 mm, horizontal 80 mm, thickness 0.5 mm) A load was applied vertically, and the minimum load at which the surface was damaged when scratched was measured.
[0029]
(12) Tapping strength
A test piece having a tapping test boss having an outer diameter of 9 mm, an inner diameter of 2.5 mm and a height of 19 mm on a plate having a diameter of 40 mm and a thickness of 3 mm was manufactured by injection molding at a resin temperature of 210 ° C. Each test piece obtained was left in a constant temperature room at 23 ° C. for 40 hours, and then a JIS type 2 screw (shaft diameter: 3.0 mm, length: 12 mm) was screwed in using an air impact drill. The number of screw holes destroyed was obtained.
[0030]
[Create polymer]
Preparation of solid catalyst components(Process 1)
Under a nitrogen atmosphere, 47.6 g (500 mmol) of anhydrous magnesium chloride, 259 ml of decane and 234 ml (1.5 mol) of 2-ethylhexyl alcohol were heated at 130 ° C. for 2 hours to form a homogeneous solution, and then phthalic anhydride was added to this solution. 11.1 g (75 mmol) was added, and the mixture was further stirred and mixed at 130 ° C. for 1 hour to dissolve phthalic anhydride in the homogeneous solution. After cooling the obtained uniform solution to room temperature, the whole amount was dripped in 2.0 L (18 mol) of titanium tetrachloride kept at −20 ° C. over 1 hour. After completion of the dropwise addition, the temperature of the mixed solution was raised to 110 ° C. over 4 hours, and when it reached 110 ° C., 26.8 ml (125 mmol) of diisobutyl phthalate was added and stirred at 110 ° C. for 2 hours. After completion of the reaction, the solid component was collected by hot filtration. Thereafter, this reaction product was suspended in 2.0 L (18 mol) of titanium tetrachloride, and then reacted at 110 ° C. for 2 hours. After completion of the reaction, the solid component was again collected by hot filtration, and washed 7 times with 2.0 L of decane at 110 ° C. and 3 times with 2.0 L of hexane at room temperature.
[0031]
TiCl _Four [C ₆ H _Four (COO-iso-C _Four H ₉ ) ₂ Preparation of(Step 2) 27.8 g (100 mmol) of diisobutyl phthalate was added dropwise to 1.0 L of hexane containing 19 g (100 mmol) of titanium tetrachloride over about 30 minutes while maintaining 0 ° C. After completion of dropping, the temperature was raised to 40 ° C. and reacted for 30 minutes. After completion of the reaction, the solid component was collected and washed 5 times with 500 ml of hexane to obtain the desired product.
TiCl _Four [C ₆ H _Four (COO-iso-C _Four H ₉ ) ₂ ] Processing(Step 3) 40 g of the solid catalyst obtained above is suspended in 600 ml of toluene and TiCl is added at 25 ° C._Four [C₆ H_Four (COO-iso-C_Four H₉ )₂ It was reacted with 10.3 g (22 mmol) for 1 hour. After completion of the reaction, 200 ml (1.8 mol) of titanium tetrachloride was added and reacted at 110 ° C. for 2 hours. After completion of the reaction, the solid component was collected by hot filtration, and then the reaction product was suspended in 600 ml of toluene and 20 ml of titanium tetrachloride (0.18 mol) and reacted at 110 ° C. for 2 hours. After completion of the reaction, the solid component was again collected by hot filtration, and washed 5 times with 1.0 L of toluene at 110 ° C. and 3 times with 1.0 L of hexane at room temperature.
[0032]
Prepolymerization catalyst component
In an autoclave with an internal volume of 3 L under nitrogen atmosphere, 500 ml of n-heptane, 6.0 g (0.053 mol) of triethylaluminum, 3.1 g (0.017 mol) of t-butyltrimethoxysilane and the above were obtained. 100 g of the solid catalyst component was added and stirred for 5 minutes in a temperature range of 0 to 5 ° C. Next, propylene was supplied into the autoclave so that 10 g of propylene per 1 g of the solid component was polymerized, and prepolymerized at a temperature range of 0 to 5 ° C. for 1 hour. The obtained prepolymerization catalyst was washed 3 times with 500 ml of n-heptane and used for the following polymerization.
[0033]
Preparation of polypropylene resin component (A)
(High MFR polypropylene resin: PP-1)
Polymerization was carried out using one autoclave with a stirrer having an internal volume of 60 L in a nitrogen atmosphere. 2.0 g of the prepolymerized catalyst component prepared by the above method, 11.4 g (100 mmol) of triethylaluminum, 5.9 g (33 mmol) of t-butyltrimethoxysilane were added, and then 18 kg of propylene and the MFR of the polymer were 300 g / min. Then, hydrogen was supplied so that polymerization was performed at 80 ° C. for 30 minutes. Unreacted gas was purged to obtain the desired propylene. The obtained PP had an MFR of 335 g / 10 min and an isotactic pentad fraction (P) of 0.994.
[0034]
(Polypropylene resin: PP-3)
Polymerization was performed using an autoclave equipped with a stirrer with an internal volume of 60 L in a nitrogen atmosphere. 2.0 g of the prepolymerized catalyst component prepared by the above method, 11.4 g (100 mmol) of triethylaluminum, 5.9 g (33 mmol) of t-butyltrimethoxysilane, and then 18 kg of propylene and a polymer MFR of 30 g / 10 Hydrogen was supplied so that the amount of water reached 30 minutes, and polymerization was carried out at 80 ° C. for 30 minutes. Unreacted gas was purged to obtain the target PP. The obtained PP had an MFR of 31.4 g / 10 min and an isotactic pentad fraction (P) of 0.994.
[0035]
(Polypropylene resin: PP-4)
For comparison, 6.0 g of AA-type titanium trichloride manufactured by Tosoh Akzo Co., Ltd. and 23.5 g of diethylaluminum chloride were used as catalyst components, and 18 kg of propylene and hydrogen were supplied so that the MFR of the polymer was 300 g / 10 min. Polymerization was carried out at 70 ° C. for 30 minutes. The obtained PP had an MFR of 308 g / 10 min and an isotactic pentad fraction (P) of 0.964.
[0036]
Polymerization of ethylene-propylene-alphaolefin terpolymer (B)
(Ethylene-propylene-butene-1 copolymer: EPBR)
After maintaining an autoclave with an internal volume of 60 L at 30 ° C. or less, 500 mg of a prepolymerization catalyst similar to that used for the polymerization of PP, 11.4 g (100 mmol) of triethylaluminum, 5.8 g (33 mmol) of diisopropyldimethoxysilane were added with propylene and After press-fitting with butene-1, the temperature was quickly raised to 50 ° C. After reaching 50 ° C., polymerization was carried out by continuously supplying ethylene so as to obtain a predetermined total pressure. The desired copolymer was obtained by changing the polymerization time at each stage.
After a predetermined time, methanol was injected into the autoclave to stop the polymerization. After removing all the gases, the desired copolymer was obtained. The obtained copolymer had MFR = 5.5 g / 10 min, ethylene content of 28 wt%, propylene of 39 wt%, and butene-1 of 33 wt%.
[0037]
Preparation of talc masterbatch
  PP-3 above: 50 wt%Talc with an average particle size of 1.3 μm (hereinafter referred to as “talc A”): Supermixer (SMV20 type) manufactured by Kawada Seisakusho Co., Ltd., which is obtained by adding commercially available antioxidant BHT: 0.08 phr, Irganox 1010: 0.05 phr, calcium stearate: 0.1 phr to a 50 wt% mixture. ) Using a twin screw extruder (Toshiba Machine Co., Ltd. TX-37) and melt-kneaded at 200 ° C. to prepare a talc masterbatch (hereinafter referred to as “masterbatch D”).It was.
[0038]
Creating a calcium carbonate masterbatch
What added 50 wt% of light calcium carbonate (hereinafter referred to as “charcoal cal A”) having an average particle size of 0.3 wt. Mixing and melt-kneading were carried out by the above method to prepare a calcium carbonate master batch (hereinafter referred to as “master batch A”).
[0039]
(Example 1)
Polypropylene resin (PP-1): 45 wt% as a part of component (A), MFR = 12 g / 10 min as component (B), hydrogenated styrene-butadiene block copolymer having a styrene content of 20 wt% (manufactured by Asahi Kasei) Tuftec H1052: hereinafter referred to as SEBS)): 100 wt parts of resin composition comprising 25 wt% and masterbatch D: 30 wt%, sodium-2,2'-methylene-bis- (4,6-di) as a nucleating agent -T-Butylphenyl) phosphate (NAIL from Asahi Denka) 0.4 parts by weight, further commercially available stabilizer BHT: 0.08 parts by weight, Irganox 1010: 0.05 parts by weight, calcium stearate: 0.1 weight part was added and it melt-kneaded at 200 degreeC using the twin-screw extruder (KTX-37), and produced the resin composition. Using the obtained resin composition, a test piece was prepared and the physical properties were measured. The results are shown in Table 2. The dispersion parameter (σ) of the composition was 3.1.
Since only talc was used instead of calcium carbonate as a filler, not only the gloss was lowered and the moldability was slightly lowered, but the molded product became gray.
[0041]
(Comparative Example 1)
Polypropylene resin (PP-1) used in Example 1 as a part of the component (A): 60 wt%, SEBS: 25 wt%, powdery charcoal A not used as a masterbatch: 7.5 wt%, and a similar powder form The same amount of the same additive as that used in Example 1 was added to 100 parts by weight of the resin composition composed of 7.5% by weight of talc A, and melt-kneaded in the same manner to prepare a resin composition. Using the obtained resin composition, a test piece was prepared and the physical properties were measured. The results are shown in Table 2. The dispersion parameter (σ) of the composition was 5.0. This was because the dispersion of component (B) was poor and the average particle size could not be measured.
When the same calcium carbonate and talc as in Masterbatch C used in Example 7 were used in the powder state without making a masterbatch in advance, the gloss and appearance (flow mark) were lowered, and problems still remained.
[0042]
(Comparative Example 2)
Resin composition consisting of polypropylene resin (PP-4) having an isotactic pentad fraction (P) of 0.964 as part of component (A): 45 wt%, SEBS: 25 wt%, masterbatch A: 30 wt% The same amount of the same additive as used in Example 1 was added to 100 parts by weight of the product, and melt-kneaded in the same manner to prepare a resin composition. Using the obtained resin composition, a test piece was prepared and the physical properties were measured. The results are shown in Table 2. The dispersion parameter (σ) of the composition was 2.1.
Since PP having a low isotactic pentad fraction (P) of component (A) is used, there is a problem in that the tapping strength, scratch resistance, and impact resistance are lowered.
[0043]
[Table 1]

[0044]
【The invention's effect】
The polypropylene resin composition of the present invention is a resin composition in which a polypropylene resin, a copolymer containing a portion composed of ethylene and an alpha olefin having 3 or more carbon atoms, and talc having an average particle size of 3 μm or less are kneaded and dispersed extremely uniformly. It is a thing.
As a result, this polypropylene resin composition has tapping strength, surface hardness (scratch resistance), impact resistance at room temperature and low temperature (−30 ° C.), flow characteristics ( It is excellent in the flow mark), etc., and has a well-balanced characteristic property value, so that it can be used as an excellent raw material as a material for injection molding and sheet molding.

Claims (6)

(A) MFR (JIS K-7210, melt flow rate measured according to Table 1, Condition 14) is 100 to 1000 g / 10 min, and propylene chain isotactic pentad fraction (P) is 0.980. The above polypropylene resin (the result of kneading all the polypropylene resins contained in the resin composition) ... 40 to 85 wt%,
(B) a component composed of one or more copolymers including a portion composed of ethylene exceeding 10 wt% and an alpha olefin having 3 or more carbon atoms (provided that propylene is at most 80 wt%) (provided that ethylene and 3 carbon atoms herein) The above-mentioned alpha olefin is not limited to the raw material monomer but means that the copolymer has as a structural unit.)... 50 to 10 wt%
(C) Talc with an average particle diameter of 3 μm or less: 3 to 20 wt%
A composition comprising:
(1) MFR of the whole composition is 25 g / 10 min or more, and (2) Dispersion parameter (σ) of talc of (C) in resin component consisting of (A) and (B) (horizontal axis A polypropylene resin composition characterized in that the area fraction of talc, the vertical axis is expressed by frequency, and the standard deviation when approximated by a Gaussian distribution is 4.5 or less. The polypropylene resin composition according to claim 1, wherein the copolymer of the component (B) is a copolymer containing a portion composed of ethylene and an alpha olefin having 4 or more carbon atoms. The copolymer of component (B) is an ethylene-propylene-alphaolefin terpolymer comprising 10 to 80 wt% of ethylene, 80 to 10 wt% of propylene, and 10 to 80 wt% of an alpha olefin having 4 or more carbon atoms. Item 3. The polypropylene resin composition according to Item 1 or 2. The polypropylene resin composition according to claim 1 or 2, wherein the copolymer of component (B) is a hydrogenated product of a styrene-butadiene block copolymer or a random copolymer having a constitutional unit derived from styrene of 40 wt% or less. object. The polypropylene resin composition according to any one of claims 1 to 4, wherein the number average particle diameter of the copolymer particles of the component (B) dispersed in the polypropylene resin of the component (A) is 3 µm or less. Isotactic pentad constituting talc (C) as a part of polypropylene resin (A) having an MFR of 100 to 1000 g / 10 min and an isotactic pentad fraction (P) of 0.980 or more Melting and kneading with the remainder of the polypropylene resin (A) and the copolymer (B) after previously kneading with a polypropylene resin having a fraction (P) of 0.960 or more and an MFR of 50 g / 10 min or less. The method for producing a polypropylene resin composition according to any one of claims 1 to 5, characterized in that: